The Research Of Preparation And Properties Of Polyurethane Elastomers

This paper mainly focused on the systematic research of the preparation and the propertiesof polyurethane elastomers (PUEs) of three kinds: TDI based PUEs, high-performance PUEsand epoxy-modified polydimethylsiloxane modified PUEs. As for the study of TDI basedPUEs, the influences of the isocyanate index R and the type and molecular weight of polyolon the mechanical and heat aging resistance properties of the elastomers were mainlydiscussed; as for the high-performance PUEs, the mechanical and heat aging resistanceproperties of NDI based PUEs and PPDI based PUEs were studied, and the effect of the chainextender coefficient on the properties of PUEs was also discussed; as for the epoxy-modifiedpolydimethylsiloxane modified PUEs, epoxy-modified polydimethylsiloxane(epoxy-modifiedsilicone oil) was applied to modify TDI based PUEs and the effect of the epoxy-modifiedsilicone oil content on the mechanical and heat aging resistance properties of the elastomerswas studied.The research results of TDI based PUEs showed that when the isocyanate R equaled to 2,the mechanical and processing properties of the elastomers were the best; and thepolycaprolactone polyol with the molecular weight 1000 resulted in much better mechanicalproperties and retention rates of mechanical properties.The results of high-performance PUEs showed that NDI based PUEs had the maximumtensile strength and tear strength among the three kinds, the elongation at break of PPDI basedPUEs was the largest, after the heat aging resistance treatment 120℃×24h, the retention ratesof mechanical properties of NDI based PUEs were the largest, i.e. their heat aging resistanceproperties were the best; while the viscosity of TDI based prepolymer was much smaller andits pot life was longer, so the processing properties of TDI were the best; besides, the tensile strength, tear strength and modulus at 200% all increased first and then decreased with theincrease of the chain extender coefficientα, and whenαequaled to 0.90, the above threevalues respectively reached their maximums.The results of epoxy-modified polydimethylsiloxane modified PUEs showed that themechanical properties of the modified elastomers became worse with the increase of theepoxy-modified polydimethylsiloxane content; after the heat aging resistance treatment, theretention rates of mechanical properties of the modified elastomers obtained some increasescompared with the common ones, and when the content reached 6%, the comprehensiveretention rates of mechanical properties were the best, i.e. the heat aging resistance propertiesof the modified PUEs with polydimethylsiloxane content of 6% were the best.